Art of reducing metals



July 9, 1946. c. R. sELlGER ART OF REDUCING METALS Filed June l2, 1942 f7@ WW2 la? @ENEL/a SEZ @65 Patented July 9, 1 946 ART oF REDUCING METALS Cornelia R. Seliger, Chicago, Ill., assignor to Henry Blech, Chicago, Ill.

Application June 12, 1942, Serial No. 446,789

The: invention relatesto the art of reducing metals to granular form and particularly to granules having internal lubrication I 'I'he invention concerns metals such as aluminum, antimony, copper, iron, lead, magnesium, tin, and zinc.

It is an object of the invention to produce in an efficient and inexpensive way metal granules which have a porous structure.

A further object of the invention constitutes the provision of metal granules capable of retaining a lubricant both externally and internally, so that when a mass of such granules is compressed into solid form, the product is permeated witha lubricant and has external lubri=Y cation. f

A further object 'constitutes the steps of melting the metal, mixing it with a lubricant or lubri- 'cants,\ and subsequently reducing the metal .to

crystalline particles with irregular surfaces and cellular structure, so that the lubricant is occluded' inthe particles and the irregular surface cause eil'c-ctive adherence of lubrication exter- 4rlally applied thereto.

It is a still further object to melt metal and subject the molten metal to a mechanical reduction, so as to produce particles of scoriaceous structure, whereby material applied thereto becomes firmly adherent thereto.

With these and other Objects in view which will becomev apparent from a perusal of theinvention, the latter comprises the novel steps of a method described in the following specification, particularly pointed out in the claims forming a part hereof a d illustrated in the accompanying drawing n which Fig. 1 is a side view rof an apparatus adapted to v carry out the method. y

Fig. 2 is a longitudinal section through a portion of the apparatus, A

Claims. (Cl. 83-91) l is carried out.

2 which is retained in the molten metal because oxygen is excluded.

The lubricant whichl is added to the molten metal is employed in quantities from three to six parts by weight of lubricant for each one hundred parts by weight of metal.

The moltenmetal, while cooling off slowly, is subjected to stirring whereby all of thelayers of the molten mass are repeatedly brought to the top and exposed to surface oxidation. l'

Cooling of the molten vmass is permitted to a/ temperature below the melting point of the metal. 'at which stage the metal assumes semi-fluid or doughy consistency. Any impurities appearing on the surface are removed before the stirring A heated foraminous plate having openings ranging vfrom 2 to 6 mm. is utilized to force the doughy mass therethrough, und r continuous impacts whereby crystalline partie' es of scoriace'ous structure result.

I have found that such impacts may be effected by the use of a sledge hammer of about 20 lbs. of weight which is held by the operator and brought down on the doughy mass spread on the' heated foraminous plate and is then reciprocated under g pressure sumcient to disintegrate the mass.

through the openings in the plate. 'This procedure is repeated until all of the mass has been forced through the plate. 'I'he best results are obtained when the hammer engages the doughy mass with an edge to obtain a sharp impact.

Fig. 3 is a section on the line 3 3 loi Fig. 2, and

Fig. 4 is a section on the line 4-4 oi' Fig. 1.

In carrying out my invention, I first melt the metal and then permit it to cool slowly. A solid lubricant, such as graphitemica, talc, chalk, or oxide of zinc or stearic acid is added to the metal whilein molten 'condition and having doughy consistency.

It is understood that the particular lubricant selected varies with particular requirements. If preferred, colloidal graphite or lubricating oils may be used, depending upon the melting point of the particular metal and the use to'which it is put.

For iron andcopper colloidal graphite is used In commercial application, the apparatus more or less diagrammatically shown in the accom-- panying drawing' is utilized, in which I0 designates a support on which an electric furnace is placed. The support I0 rests on a platform Il placed on I-beams I2. An electricheating furnace I4 is placed on the support I 0 and is provided with a. top I5. having openings for the admission of air and for affording access to the top surface of the molten metal in said furnace, to remove impurities. A.

The top II is provided with a'pair of bearings I6 in which a shaft I1 is iournaled having at one end 'a pulley I0 and provided at the other end with a bevel gear I9 in mesh with a mating gear 20 on a vertical shaft 2l .iournaled in the top IB.

The shaft 2| extends to a point short of the bottom of the furnace and has a plurality of blades 22 which stir the molten metalupon rotation of the shaft.

. The furnace is provided with an outlet 23 normally closed by a gate valve 24 having a rack 2i in mesh with a pinion A28.

- dougniy Upon rotation of the pinion 26 the gate valve may be raised to permit vthe discharge of the doughy metal by a spout like a trough,

The screen is mounted in a box frame having side walls 29 and end walls 38 and placed on supports 3|.

A plurality of screens 32, 33 and 34 are mounted in ,said box frame with progressively coarser mesh. Hoppers 35 depend from each screen section to discharge screenings into receptacles 38 placed on the platform I i.

A longitudinal shaft 31 is journaled in bearings 38 at the end walls and extends through a hollow shaft 39 which is provided with a screw conveyor 40.

The portion of the shaft 31 within the screen 28 has a plurality of hammers or strikers 4| shaped to engage the' material with a sharp edge.

The shaft 33 has a gear 42 in mesh with a. pinion 43 on a shaft 44v to which power is imparted from a motor 45.

A pinion 46 is Aspliried on the shaft 31 and meshes with a gear 41 on the shaft 44 so that the shaft 31 rotates with greater speed than the hols low yshaft 33. A bell crank lever '48 engages a pulley 49 fast on the shaft 31 to impart reciprocating movement to the shaft 31.

The screen 28 is heated by a plurality of gas burners 50.

In use the metal is molten in the furnace and any impurities appearing on top of the molten mass are removed through the open top I5. The molten metal is stirred and permitted to cool to a temperature from 50 to 100 below its melting temperature to obtain doughy consistency. y

Thereupon the gate valve is opened and `the metal discharged by the spout 21 to the screen. 'I'he shaft 31 being rotated and reciprocated subiects'the doughy metal to impacts and friction whereby the metal is formed .into granlules of cellular structure. Y

The fine granules pass while the coarser granules are carried to the right, as viewed in Fig. l. bythe screw conveyor` and according to size, pass respectively through the screens32, 33 and 34, and collect in the receptacle 38 placed therebeneath.

Very` coarse granules reach the end spout 8| and are discharged in an end receptacle 52.

Thereafter the granules are placed under high pressure and thereby formed into a homogeneousl mass. The pressure .iluctuates between. ten thousand 4and one hundred thousand pounds of pressure per square inch, depending on the metal or combination of metals use n In some cases the metal granules are placed in moldspsublectd to high pressure, and subsequently sintered. The best results were obtained when sintering was carried out for a period of approximately twenty minutes.

After sintering, -the mass is quenched in an oil or water bath. The granules maybe mixed `with external lubrication prior to being subjected to compression so that a filler of lubrication is provided between the granules and due to compression, absorption of the lubricant by the granules iscaused.

21 to a screen 28 shaped through the screen 2a plied to lead.

4 While the invention is described in its preferred embodiment, numerous changes and modifications may be made without'detracting from the spirit of the invention.

I, therefore, do not limit myself to the nett-nis or the particular sequence of steps enumerated, but claim my invention as broadly as the state of the art permits.

I claim:

1. The method of reducing iron to particle form, including the steps of melting said iron, permitting said iron to cool to a semi-liquid doughy consistency in thetemperature ranging substantially from 50 to 100 F. from its melting point Whilevbeing puddled, maintaining the iron at that range of temperature while forcing the semi-liquid iron by impacts through a heated foraminous plate, and cooling the particle to solidilcation.

2. The method of producing iron granules permeated .by a l bricant, including the steps of melting the iron, adding thereto colloidal graphite, Awhile puddling the metal, permitting the metal to cool to a doughy semi-liquid consistency in the` temperature rangingsuhstantially from 50 to 100 F. from its melting point, maintaining the iron at that range `oi temperature while forcing the metal through a foraminous plate under impacts, and cooling the granules to solidiilcation.

3. The method of producing iron granules perp meated by a lubricant, including the .steps of melting the iron, adding thereto colloidal graphite, while puddling the metal, pennitting the metal to cool to a doughy semi-liquid oonsistency in the temperature ranging substantially from 50 to 100 F. from its melting point, maintaining theiron at that range of temperature while` forcing the metal through a heated foraminous plate under impacts and friction, and cooling the granules to solidiiication.

4. The method as set forth in claim l applied to the reduction of copper.

5. The method as set forth in claim 2 applied to the reduction of copper.

6. The method as set forth in claim 1 as applied to'aluminum.

'7. The method as set forth in claim 2 as applied to aluminum.

8. The method as set forth in claim 1 as ap- 9. The method as set forth in claim 1 as applied to magnesium. 10. The method as set forth in claim'l as applied to tin.

11. The method as plied to zinc.

12. The method as set forth in claim 2 as applied to lead.

u13. The method as set plied to magnesium.

14. The method as set plied to tin. 'A

15. The method as set forth in claim 2 as applied to zinc.

set forth in claim 1 as apforth in claim 2 as apforth in claim 2 as ap- CORNEHAR. Bauamt. 

